High efficiency diffractive coupling lenses by three-dimensional profiling with electron-beam lithography and reactive ion etching

Abstract

Single diffractive lenses with submicrometer feature sizes are realized with binary, multilevel, and blazed reliefs using computer-aided design methods, three-dimensional (3D) profiling algorithms, direct write e-beam lithography, reactive ion etching, antireflection coating, and wafer dicing. Depending on the relief profile, maximum diffraction efficiencies of more than 70% for lenses with a high numerical aperture of 0.5 were measured and aberration-free imaging was observed. In order to enhance the diffraction efficiency we present a method for obtaining Fresnel grating lenses and a flexible 3D shaping of the resist mask for the dry etch process.

Microreplication in a silicon processing compatible polymer material

“…Several methods for microlens fabrication have been presented. Thermal reflow techniques [2] have most frequently been used for refractive lenses, whereas direct-write methods such as electron-beam lithography [3] and laser ablation [4] have been the dominant processes for diffractive microlens fabrication. In recent years, methods such as hot embossing have enjoyed increasing popularity for production of both types of lenses due to the convenience of polymer replication processes.…”

Three-dimensional design in electron-beam lithography

“…[1][2][3][4] For these the total area has to be exposed with a continuously variable dose, which of course needs proximity correction as well. [1][2][3][4] For these the total area has to be exposed with a continuously variable dose, which of course needs proximity correction as well.…”